Magnetic resonance (MR) imaging is a useful noninvasive method for imaging the internal components of a wide array of objects. Its noninvasive imaging of tissue in living subjects, especially humans, is highly valued in the medical field.
Phase information obtained in MR imaging applications may contain valuable information useful in a number of imaging techniques, including susceptibility weighted imaging techniques of the type described in U.S. Pat. No. 6,658,280, issued Dec. 2, 2003, the entire contents of which are incorporated herein by reference.
However, phase based MR imaging techniques may suffer from unwanted artifacts caused by phase wrapping or aliasing. For example, SWI typically utilizes phase information obtained using a gradient echo sequence with a long echo time (TE). However, due to long TE, phase aliasing occurs. For the purpose of SWI, phase wraps can be removed by conventional region growing methods or homodyne filtering. However, region growing phase unwrapping methods are not always reliable and conventional homodyne highpass filtering induces undesired artifacts.